New way to farm boosts climate, too
‘Organic no-till’ combines best of two methods and sequesters most carbon. But can it work consistently?
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“Can it help mitigate? Yes,” he says. “Is it the long-term, major solution? No.”Skip to next paragraph
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Part of the reason organic and no-till farming are only temporary solutions, he says, is that the ability of soil to sponge up more and more carbon eventually runs out.
“My own work shows [that] the more beat-up [the soil] is to begin with, the better response you get subsequently with carbon sequestration,” he says. “But after 10 years, 20 years, maybe it’s 50 years, we’re going to plateau out.”
Another important question is how to get farmers to embrace new methods.
“Farmers are very conservative people by nature,” farm director Moyer says. “When you ask a farmer to adopt a new technology, they are literally risking the farm, their home, and their income on this new technology.”
The allure of reduced fuel costs and better prices for organic produce may not be enough. Mr. Hepperly, the Rodale Institute research director, says that for a switch-over to occur in this country, the government must enact a system that pays farmers to sequester carbon. Carbon trading is already being experimented with at the Chicago Climate Exchange and elsewhere. The Rodale Institute is advocating that such a trading system be enacted in the next farm bill in 2012.
“This will allow farmers to see a real economic motivation to resolving these core issues,” Hepperly says.
Mr. Burras concurs: “I strongly support the idea of green payments,” he says. “Any practice that results in better carbon sequestration results in better environmental quality across the board.”
How does organic no-till farming work?
One of the challenges of growing crops is controlling weeds, but different types of farmers come at the problem in different ways. “No-till” farmers use large amounts of chemical herbicides to kill weeds, but don’t plow the soil. “Organic” farmers plow and cultivate extensively – another way to manage weeds – but don’t use any herbicides. Although each method has its advantages, until recently it seemed they were incompatible: Organic farmers till often; “no-till” farmers use herbicides.
The key to organic no-till is that it relies instead on a third method of weed control: cover crops. Cover crops are planted between rotations of food crops and, besides holding soil in place and crowding out weeds, also serve to replenish soil nutrients.
For example, if an organic no-till farmer intends to plant corn in the spring, he might plant that field the previous autumn with a cover crop of hairy vetch. The hairy vetch will put nitrogen back into the soil (which is important, because corn requires a lot of nitrogen to grow) and also keep the ground covered through the winter.
In the spring, once the hairy vetch crop is in full bloom, the farmer will roll it down using a special piece of equipment called a roller-crimper attached to the front of a tractor. At the same time, a no-till planter attached to the back of the tractor will plant the corn crop.
When the cover crop dies, killed by the roller-crimper, it functions as a weed-suppressing mulch. If everything goes as planned, the corn will grow up through the mulch, while the weeds will be stifled.
Researchers point out that organic no-till is not necessarily an all-or-nothing proposition. No-till farmers can incorporate elements of it to reduce the amount of herbicide they use, and organic farmers can employ it to reduce their tillage.
The same concepts of organic no-till farming can be applied on a much smaller scale to home gardening, although the actual equipment and methods involved are different. Here’s a link to an organic gardening blog that describes how to do it.